Approved in 2017 for adults with type 2 diabetes, Ozempic has now become a blockbuster weight loss drug.
Like many Americans, Marissa Montanino, a 36-year-old aesthetician, wanted to try Ozempic, a highly popular diabetes drug, seen as revolutionary in combating obesity.
"I was exercising sometimes three times a day," Montanino told AFP. "I was eating really, really healthily... and nothing was changing," she added.
"I had already heard about Ozempic, and then I started seeing other people taking it, like celebrities, who suddenly were slimming down very quickly," she said.
While officially approved for type 2 diabetes, Ozempic is prescribed off-label for weight loss.
Yet Montanino feared the risk of gastrointestinal side effects that can come with the injectable medication from the Danish company Novo Nordisk.
"I was afraid, I was very anxious," she said. "I am terrified of nausea".
When she finally decided to try it, her doctor did not prescribe Ozempic. She instead was prescribed a customised drug that included the same active molecule as in Novo Nordisk's patented injections: semaglutide, which signals to the brain that you are full.
Such customised treatments, known as compound drugs, have been used in the United States for a long time when a patient has an allergy for instance.
More than 40 per cent of the US population suffers from obesity, a sign of a major public health crisis and a massive market for these new drugs like Ozempic, given their effectiveness.
"The main problem is that it is now challenging to obtain the treatments," said researcher and physician Samuel Klein of Washington University in St. Louis. "There are not enough drugs manufactured".
Ozempic has recently been out of stock after gaining popularity on social media for its success in causing weight loss.
The US Food and Drug Administration (FDA) has classified semaglutide and tirzepatide - a molecule used in Eli Lilly's drugs for diabetes and obesity - as currently in "short supply."
Concerns over copies
This designation lifts some restrictions, allowing some pharmacies to create compounded drugs that are "essentially copies of approved drugs," according to the FDA.
Many Americans are turning to these options, which are sometimes cheaper, but experts and authorities warn of potential associated risks.
Dr Andrea Coviello, an obesity specialist, expressed concerns for patients ordering such drugs, often online.
If some have lost weight, "we do not know exactly what they are receiving," the professor at the University of North Carolina said.
Marissa Montanino, standing at 1.53 metres, details going from around 71 kg to less than 60 kg in less than six months thanks to her weekly injections. She aims to lose two more kilos.
Among the people she communicates with who are also taking weight loss treatments, "everyone is very happy," and only one person takes a brand name medication, Wegovy, which is also produced by Danish company Novo Nordisk.
'Comfortable in my skin'
US authorities said in late Octoberthat they had received "adverse event reports after patients used compounded semaglutide".
"Patients and health care professionals should understand that the agency does not review compounded versions of these drugs for safety, effectiveness, or quality," the FDA added.
A simple online search shows that several companies offer weight loss medication delivered by mail, with prices much lower than brand-name drugs, but not necessarily cheaper for those with health coverage that covers FDA-approved medications.
Marissa Montanino spent $300 (€275) for three months of treatment, but with the gradually increasing dosage, this could turn into $300 per month.
Novo Nordisk and Eli Lilly, which already earn billions of dollars from these drugs, have a vested interest in these molecules no longer being considered "in short supply" and are bolstering their production capacity.
Both companies have also filed several complaints against pharmacies producing compounded drugs similar to their products.
Despite the uncertainty, Montanino is considering taking this treatment "for life," if possible.
She celebrated her weight loss and that of her husband, who shed 22 kg, by retaking wedding photos.
"I feel comfortable in my skin. I am very pleased with how my clothes fit me. I hate to say this... But it makes me feel better."